Pakistan Army has launched the much-awaited major ground offensive to flush out Taliban from their stronghold ofWaziristan tribal region and immediately ran into heavy resistance. Backed by tanks and fighter jets, troops were locked in fierce clashes with Taliban, who were reported using heavy weapons, to hold back the army advance. Militants armed with heavy weapons attacked troops at Sharwangi, one of the first Mehsud- dominated areas they encountered.As fighter jets bombed Taliban bases, an estimated thirty to forty thousand troops advanced from three directions towards areas inhabited by the Mehsud tribe, the main stronghold of the banned Tehrik-e-Taliban Pakistan led by Hakimullah Mehsud.Before the tanks and troops rolled out, the government clamped indefinite curfew in the entire Waziristan region to ensure that the movement by soldiers was not interfered with. The offensive in Waziristan follows months of airstrikes by fighters and helicopter gunships intended to soften the Army's advance into the terrorists’ haven. Pakistani forces are reported to be heading for Makeen and Ladha, the two main towns in Waziristan dominated by supporters of slain Taliban leader Baitullah Mehsud. The military mobilisation began after leaders of Pakistan's major political parties yesterday gave their backing for efforts to root out extremism and militancy and restore the government's writ in areas controlled by militants.